The state of California's water supply is in a third year of drought and is prompting the Governor Jerry Brown to call a drought emergency.

State and federal water officials met in Sacramento on earlier this month to discuss diminishing water resources in rivers and reservoirs, many of which have dropped to levels that cannot be lowered further, they said. State officials expressed concern for how to get adequate water to cities if the drought deepens. Meanwhile, some farmers in the Central Valley have seen their water allocations eliminated completely.

Water conservation practices during wet years and a 10 percent water-use reduction have left Hetch Hetchy Reservoir -- Palo Alto's water source -- with enough water Nicole Sandkulla, CEO and general manager of the Bay Area Water Supply & Conservation Agency, told the Weekly Jan. 7. But she urged residents to conserve water whenever they can.

"It's obvious that this is a dry California year," she said, adding that the agency is in a "wait-and-see mode."

The agency is composed of 26 cities receiving drinking water from Hetch Hetchy. Hetch Hetchy is run by the San Francisco Public Utilities Commission (SFPUC).

Water officials in Sacramento did not have a rosy view of rainfall through March. They asked Gov. Jerry Brown to declare the emergency in February but decided to immediately ask for the emergency after learning that farmers anticipating water will plow their fields this month to plant crops. Officials said the emergency should be declared before plowing occurs, since the dry, plowed land could create dust-bowl conditions, such as dust storms, if farmers later lose their water allocations.

A similar scenario occurred in November 1991, when winds whipped up plowed, desiccated soil, causing a blinding dust storm that caused a 100-car pileup on Interstate 5 and trapped hundreds of Thanksgiving holiday drivers in the San Joaquin Valley, they said.

Hetchy Hetchy water comes from the Sierra snowpack, which is currently at 20 percent of normal levels, according to state officials. But Sandkulla noted that the water year begins in late October to early November. "It's still early in the water year," she said.

More than half of precipitation in the Sierras occurs between December and February, she said. A final determination of the water situation will take place in mid-April, she said.

If a catastrophic drought were to occur, drought allocations for SFPUC water have distinct rules and a formula about who gets water, she said. The agreement allows some flexibility if there is a system-wide cutback greater than 20 percent. "But we've never had that happen," she said.

The meeting at the California State Board of Food and Agriculture included presentations by the California Department of Water Resources, State Water Resources Control Board, the U.S. Bureau of Reclamation Mid-Pacific Region, water district representatives, the Northern California Water Association and other conservation agencies, who discussed U.S. Department of Agriculture drought programs.

--Craig Dremann contributed to this report.